A known sample collection is the BD Vacutainer®, used by hospitals for blood sample collection. Benefits include protection against accidental needle sticks. Vacutainer® systems use bottles with prepackaged vacuum stored in them. The vacuum is applied to a needle at the time of sample withdrawal.
Microneedles emulate the efficiency of mosquitos. The mosquito pierces the human skin using its proboscis, which is ˜1.5 to 2.0 mm in length. The proboscis consists of two tubes; the labium (inner diameter ˜40 μm) and the fascicle (inner diameter ˜20 μm), responsible for fluid injection and suction respectively. During the insertion process, through the labium, the mosquito injects saliva, which contains anti-coagulants and also acts as a local anesthetic. The fascicle acts as both a piercing mechanism and a food canal, and draws a volume of ˜1-10 μL of blood from the capillary beds at 1500 μm beneath skin surface. On average, it takes a female mosquito about 50 seconds to insert its fascicle into the human skin, and usually around 2.5 min to draw blood at a suction pressure of ˜7-8 kPa.
Technologies for fabricating various forms of microneedles are well known. The benefits of painless and safe blood withdrawal and drug administration using microneedles and small gauge needles have been established in demonstration technologies.